Heat retarder



May 21, 1935. M J, Q NYBORG 2,002,020

HEAT RETARDER Filed Dec. 3, 1954 Patented May 21, 1935 HEAT RETARDERMarinas J. C. Nyborg, Columbia Heights, Minn,

assignor of two-fifths to neapolis, Minn. I d p F. H. Hosmer, Min-Application December 3, 1934, Serial No. 755,775

2 Claims. (01. 257-168) 1 My invention provides an improved auxiliaryheater or fuel saveradapted to beinterposed in the smoke pipe between afurnace and'the chimney or hue; and generally stated, theinventionconsists of the novel devices, combinations of devices and arrangementof, parts hereinafter described and defined in the claims. The device ispreferably made from sheet' metal andcomprises inner and outercasingsspac'ed to afford an air-heating chamber surrounding the innercasing, combined with inlet and outlet passages and baflles, all aswillhereinafter more fully appear. I

In the accompanying drawings, which illustrate a commercialform of theinvention, like characters indicate like parts throughout the severalviews.

Referring to the drawings: Fig. 1 is a perspective showing the auxiliaryheater, some parts being broken away;

Fig. 2 is a vertical section taken on the line 2-2 of Fig. 1; and

Fig. 3 is a vertical section taken on the line 3-3 of Fig. 1.

Preferably, both the outer and the inner cas ings or sheet metal shellsare rectangular. The outer casing is indicated by the numeral 4 and theinner casing or shell by the numeral 5, said parts being spaced toafford an air-heating chamber 6 that extends around all four sides,under the bottom and over the top of the inner shell. The numeral 1indicates the smoke pipe leading from the furnace and the" numeral 8 thesmoke pipe leading to the outlet flue or chimney. A short pipe section 9is rigidly connected to the lower portion of the inner shell and to theouter shell 4 and projects from the latter so that the smoke pipe 1 istelescoped onto the projecting end thereof and is rigidly but detachablyclamped side, the inner shell 5 is provided with a short pipe section I2that is secured thereto and to the outer shell, preferably in alignmentwith the pipe section 9. This pipe section l2 projects from the outershell so that the smoke pipe 8 is telescoped onto the same and isclamped thereto by a split collar l3 provided at its ends with anut-equipped clamping bolt M. An air intake pipe I5 is connected to thebottom of the outer shell and opens into the bottom of the air-heatingchamber 6. This connection, as shown, is made by a thimble I6 and aclamping collar H, which latter at its ends is provided with anutequipped bolt l8. A hot air delivery pipe I9 is thereto by a splitclamping collar l0 equipped connected tothe top of the outer shell andopens from the top of the chamberG. This connection, as shown, is madeby providing the topof the shell 4, .with a flange that is telescopedinto the lower end of the pipe l9 and by a split collar ,2l,fprovi'dedat its ends with a nut-equipped bolt 22. d d d V Within the inner shell5 are vertically overlapping-bafileplates .23, 24 and 25. The bafile 24extends fromthe top of the shell 5, downward between, the upwardlyextendedbafiles 23 and 25 so as to form a tortuous air passage forthe'products of combustion through the said inner shell. As shown inFig. 3, small tie brackets 26 connect the sides of the shells land 5.

Preferably, both the outer and inner shells are provided with hingedbottom plates which, when opened, afford access to the interiors thereoffor the purpose of cleaning or repair. As shown in Fig. 3, the outershell 4, is provided with a hinged bottom plate 4a and the inner shell 5is provided witha hinged bottom plate 5a. The above noted connectionbetween the air intake pipe l5 and the bottom of the outer shell istherefore made directly to the hinged bottom plate 4a and must bedisconnected therefrom before'the said bottom plate can be dropped to aposition shown by dotted lines in Fig. 3. To normally hold the bottomplate 4a in closed position as shownby full lines in the various views,it is shown as provided with a sort of turn button 21, the hooked upperend of which is engageable with a detent 28 on the interior of theadjacent wall of the outer shell; and in like manner the bottom plate 5ais I provided with a turn button 29, the hooked upper end of which isengageable with a detent 30 on the interior of the adjacent wall of saidinner shell. a

The numeral 3|, see Fig. 2, shows a hinged damper located on the wall ofthe inner shell, preferably just above the pipe section l2. This damperwill be normally closed as shown by full lines in Fig. 2, but is adaptedto be moved into its open position indicated by dotted lines in saidview, under the action of a thermostat such as a sylphon bulb 32, shownas anchored to the pipe section 12 and connected to said damper by ashort link 33.

The air intake tube l5 may extend from the outside of the room orbuilding for the intake of fresh air or it may be a return pipe from oneof the rooms. The warm air discharge pipe ill not shown, but the smokepipe 1 will extend from the outlet thereof.

From the foregoing and from inspectionof the drawings, it is obviousthat the cross-sectional conducting capacity of the tortuous passagethrough the inner shell is much greater than that of the smoke pipes I,8, 9 and I2, so that it follows that the hot products of combustion fromthe furnace will move "very slowly through the said inner shell and'Will have plenty of time to give up or radiate the heat that wouldotherwise be carried into the flue or smoke stack and hence wasted. Ofcourse, the arrangement of baffles :makes a long travel for the heatedgases through the inner shell. Also the flow of air through the champer6 will be very slow so that it have time to absorb all of the heatradiated from the inner shell.

If the air in the chamber 6 becomes heated be yond a predeterminedextent depending 'on the setting of the thermostat, damper 3.| will beopened .so that under .the strong draft from the flue, some overheatedair will be drawn .into the interior of the inner shell and carried tothe chimney .or flue tl'lrough the .pipe 8. This will preventoverheating or burning of the air delivered into the room. Obviously,all of the heat that is absorbed .or taken up by this auidliary heaterwill :be saved heat, that is, the auxiliaryheater operates on heat thatwould otherwise be carried into the :chimney and wasted. It will beunderstoodthat the device described as to details of combustion to takea tortuous course therethnough, said inner and outer shells havinghinged bottom plates affording access to the interiors thereof whendropped, said air inlet pipe being detachalbly connected to anddelivering throughthe "hinged bottom of said outer shell.

.2, .An auxiliary heater comprising inner and outer shells spaced toafford an air chamber, said outer shell having air intake and outletpipes and said inner shell having smoke pipe connections leading theretoand therefrom through the walls of gsaidoutershelL-said inner shellhaving overlapping bafiles for causing the products of com- :bustion totake a tortuous course therethrough, in-which saidstructure, the innershell is provided withan peningnormally closed by damper combined with athermostat arranged to movesaid damper to an open position when the airin the .air chamber is heated beyond a predetermined temperature. p

MARI-NUS J. C. NYBORG.

